Update edit 2021 July- I managed to lose the bag of spares in a move and swallowed one of the PVC balls so here I am again ordering more.I switch to PVC or silicone retainers for medical reasons and tests and had swapped to one of the purple pieces from this set. It held up to about five months of daily use and a tube in my mouth/ throat from an ambulance ride so I'd say these hold up well. Interestingly enough it was the bottom ball I lost and it kept unscrewing itself so I believe they do degrade and strip over time- so just change it regularly- probably better for oral hygiene to boot. Oh also these hold up great to chlorahexadine, denture tablets and mouth wash along with daily brushing.The size listing has also been changed from inch increments to mm and in my case 16mm length 16g is the best. 16g isn't easy to find at least for me so thank you Amazon and to this company for selling them.I swallow a lot of jewelry parts from other brands- mainly from the mall, you know.I end up swallowing the tops/beads and after many years with this piercing cannot enunciate without a full barbell weight. I decided I wanted an iridescent, glow in the dark and rose gold option.After ordering a few other brands, all of which were double the length I needed I stumbled upon these. I ordered a 5/8 knowing there's no swelling with a 14 year old piercing and hoped for the best.It fits and looks great! All the promised pieces arrived and each one screws and unscrews fabulously. It's just the right length to sit comfortably, not overly big beads and it has no unpleasant taste.I'm glad I bought the large pack, i have enough rings to replace weekly if I want now!I have already bit on one accidentally, not even a scratch on the metal.Stellar deal with a solid product.If you have fine motor skill issues, or generally issues threading your own barbell you may want assistance. As these 5/8 is smaller than a standard starter piercing (which accommodates for swelling) the bar and bead hole are smaller and can make for a trying experience doing it oneself.